Setting capabilities as below in install-config:
--------
capabilities:
  baselineCapabilitySet: v4.14
  additionalEnabledCapabilities:
    - CloudCredential 

Continue to create manifests, installer should exit with error message that "the marketplace capability requires the OperatorLifecycleManager capability", as what is done in https://github.com/openshift/installer/pull/7495/.
In that PR, seems that only check when baselineCapabilitySet is set to None.

When baselineCapabilitySet is set to v4.x, it also includes capability "marketplace", and needs to do such pre-check.

    4.15/4.16

    Always

    1. Prepare install-config and set baselineCapabilitySet to v4.x (x<15)
    2. Create manifests
    3.
    

    Manifests are created successfully.

    Installer exited with error message that something like "the marketplace capability requires the OperatorLifecycleManager capability"